Polymers of carbon monoxide and olefins generally referred to as polyketones are well known in the art. The class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon are of particular interest among polyketone polymers. This class of polymers is disclosed in numerous U.S. Patents assigned to Shell Oil Company, exemplified by U.S. Pat. Nos. 4,880,865 and 4,818,811 which are incorporated herein by reference. Polyketone polymers display a well balanced set of mechanical properties which make them particularly useful as engineering thermoplastics.
Other materials having useful properties have also been formed from the combination of various olefins and carbon monoxide. Among these, are relatively low molecular weight materials comprising oligomers or low molecular weight polymers. In this case, however, a monomer other than carbon monoxide and ethene comprises at least 20% wt of the total weight of the polymer. Two olefinic monomers are ordinarily used such as ethene and propene with a relatively high percentage of each (on a weight or molar basis) compared to the linear alternating aliphatic polyketones used as engineering thermoplastics. The monomeric mix will typically include about 50% mole (based on total weight of polymer) CO and about 50% mole of olefins with at least about 30% by weight of the total olefin content comprised of C.sub.3 or higher olefins.
These oligomers or low molecular weight polymers can be employed as thermosets. Depending upon the composition and method of preparation, many will still advantageously exhibit many properties ordinarily associated with thermoplastics under a range of conditions. In such applications they are cured with a curing agent which is generally an amine. Curing may be achieved in the presence of an acid catalyst. Such resins are preferable to existing thermosets in a variety of applications due to reduced environmental nuisances, ease of use, and property mix.
One application of these thermosets is as an adhesive. More particularly, they are useful as glues for wood composites in the preparation of plywood and flake or particle board. To this point, the wood composite industry has generally used adhesives such as urea formaldehyde resins and phenol formaldehyde resins. However, many of the wood composites prepared with them are losing favor in important market segments even though the demand remains generally high for a high impact resistant wood composite with good dimensional stability in the presence of moisture. Much of this is attributable to environmental and safety factors associated with the systems.
Wood glue compositions based on neat olefin/CO resins and amine curing agents have been previously prepared. While these neat glue systems provide good adhesion, their viscosity and pot life are not ideal for many commercial applications. Lowering their viscosity and increasing their pot life would extend the range of applications for which olefin/CO resins could be used. In particular, they could be made much more suitable for use in the production of plywood and oriented strand board under such conditions.